1. Field of the Invention
The present invention relates to a magnetic head which uses a soft magnetic alloy film.
2. Related Art Statement
In the magnetic recording technical field, the coercive force of the recording medium such as the magnetic tape or the like has been improved for the purpose of raising the recording density. Accordingly, there has been desired a material for the magnetic core of the magnetic head exhibiting high saturated flux density (Bs).
However, the conventional ferrite magnetic head has been able to realize only the saturated flux density of about 5000 G (Gauss). Therefore, the desire for realizing the high density has not been satisfied. Therefore, a metal-in-gap-head, that is, a laminated head or a thin film head formed by sandwiching the metal magnetic laminated film by ceramic plates or the like has been disclosed.
The soft magnetic material (film) having high saturated flux density for use in various magnetic heads is exemplified by an Fe-Si-Al alloy (Sendust). Recently, non-crystal alloy film the main component of which is Co which is a ferromagnetic metal element has been developed.
Furthermore, a film exhibiting high saturated flux density and having excellent soft magnetic characteristics has been disclosed in which an alloy film (Fe-C, Fe-Si or the like) formed by fine crystal the main component of which is Fe is employed so as to reduce an influence (undesired influence which acts on the soft magnetic characteristics) from the crystal magnetic anistropy of Fe by the fining of the crystal.
However, equipment that include a magnetic head have been reduced in size and weight. Therefore, the equipment tend to be subjected to vibration due to the transport of the equipment or use under bad conditions. Therefore, the magnetic head must have excellent magnetic characteristics, wear resistance against the magnetic head, durability in terms of the temperature and corrosive atmosphere, that is, environmental resistance and vibration resistance. Therefore, the gap forming or mounting into the case must be performed by glass-deposition. Therefore, the material for forming the magnetic head must withstand the high temperature of the glass depositing process in the magnetic head manufacturing process.
However, the conventional soft magnetic alloy film made of Sendust exhibits saturated flux density of about 10000 G which is insufficient for realizing the future desire of raising the density. Although high saturated flux density of 13000 or more has been obtained from the conventional Co amorphous alloy film, the quantity of addition of Ti, Zr, Hf, Nb, Ta, Mo, W and the like which form the amorphous must be reduced when the saturated flux density of the amorphous alloy is desired to be raised. If the quantity of the addition is reduced, the stability of the amorphous structure deteriorates. As a result, it cannot withstand the temperature (about 500.degree. C. or higher) necessary for performing the glass deposition.
Furthermore, the alloy film (Fe-C, Fe-Si or the like) formed by the fine crystal the main component of which is Fe encounters crystal growth at high temperature, causing the soft magnetic characteristics to be deteriorated (the highest temperature is 400.degree. C. in the case of Fe-C). Also the above-described alloy cannot be preferably employed to be subjected to the glass deposition.